[Haskell-cafe] mixing map and mapM ?

[Brandon S. Allbery KF8NH]

On May 9, 2010, at 07:18 , wren ng thornton wrote:
> Where available, the fmap version is the most efficient. The liftM  
> function can be less efficient since it's defined generically  
> (namely with the bind/return definition above), whereas fmap can  
> take advantage of knowing the specific monad it's working on. But  
> then, not everyone defines Functor instances for their monads...


Arguably that deserves a bug report, as logically a Monad is an  
Applicative is a Functor (or read "is a" as "subset of" for pedantry).

-- 
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university    KF8NH


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